Die for mechanical joining

ABSTRACT

A die for a tool set includes a punch and a die for mechanically joining metal sheets lying flat one on top of another by shaping. An anvil and die segments together form a cavity into which the joining is carried out. The die segments are supported in a slidable manner at an angle transversely, preferably orthogonally to the cavity axis H against a spring force. A casing sleeve surrounding the die segments is essentially rectangular in cross section, open at the top and can be attached to a base body. The die segments can be supported and guided in guide slots lying parallel opposite one another in the casing sleeve. Guide mechanisms project laterally on the die segments for positive engagement in the guide slots.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 10 2006 024 112.6, filed on May 19, 2006, the disclosure of which is expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a die for mechanical joining and, more particularly, to a tool set comprising a punch and a die for mechanically joining metal sheets lying flat one on top of another by shaping.

2. Discussion of Background Information

A die is known, e.g., from EP 1 468 758 A1. In order to connect two metal sheets lying on top of one another by shaping, the metal sheets are laid in an overlapping manner between the punch and the die. The punch is lowered to the sheets and pressed onto sheets, and presses the material into the die or into the cavity formed by the die segments and the anvil. During shaping, the die segments have to shift in order to enlarge the cavity so that the displaced material can be accommodated.

The known die is round. The anvil is pressed into the die sleeve. Six die segments embodied as circle segments bear against the anvil, which respectively are guided radially outside over an appendage in radial circumferential slots in the die sleeve. In order to be able to apply a spring preload to the die segments in the radial direction, these segments are connected via a single spring lock washer (e.g., O-ring). After joining has been completed, the die segments are pulled back into their original position by the force of the spring lock washer.

In the deflection movement, the entire underside of the die segments slides on the annular support surface of the anvil. In order to be able to apply sufficient restoring force, the spring lock washer must consequently be of a correspondingly large size, which is a factor in determining the outer circumference of the die. Sheet metal parts that have complex shapes and are to be connected to one another sometimes do not provide sufficient free space at the joints to permit the use of a round die. Moreover, such a die cannot be used if the spreading path of the die segments has to be limited.

A clinching die is known from EP 0 835 701 A2. The clinching die has a rectangular outer contour. The anvil of this die is embodied on a base body. Two die segments arranged opposite one another are provided. A die sleeve is placed on the base body, which is essentially closed over its circumference and at the top has only a round cutout through which the protruding part of the die segments projects. The closed die sleeve guides the die segments and ensures they do not fall out. Spring tabs embodied in one piece with the die sleeve apply the restoring force for the spring segments. The spring tabs are embodied by double folds.

To enable the spring tabs to fulfill their function, the entire die sleeve must be made of spring steel with a spring steel thickness with an upper limit because of the spring effect. This has the disadvantage that the die sleeve is not able to absorb high support forces that are necessary when the components to be joined impact the die sleeve. In order to avoid the die being destroyed and fragments flying, a stable die protection device has to be positioned around the die. This protection device increases the working width and also the working thickness of the die so that if only limited space is available for components, this, like a round die, cannot be used. Furthermore, such a die has the disadvantage that cleaning is impeded due to the die sleeve being essentially closed over the circumference. In part, cleaning is possible only by the time-consuming dismantling of the die.

SUMMARY OF THE INVENTION

Based on the above problem, the die described at the outset is to be improved such that it can be made smaller with the same stability, and is suitable for use in component parts difficult to reach.

A die to solve the above problems comprises a casing sleeve which is essentially rectangular in cross section, open at the top and can be attached to the base body. The die segments can be supported and guided in guide slots lying parallel opposite one another in the casing sleeve. Guide mechanisms projecting laterally from the die segments are available for a positive engagement in the guide slots.

Through the rectangular embodiment of the casing sleeve, the die can be very narrow in one orientation (direction). Because the die elements are supported and guided in guide slots lying parallel opposite one another in the casing sleeve, contact surfaces at the bearing points are small, so that only slight frictional forces occur and thus correspondingly slight restoring forces are necessary. In embodiments, the bearing points are realized by bolts with a diameter of about 1 mm; although other dimensions are also contemplated by the invention. At the same time, the guide slots also ensure the die elements do not fall out. The casing sleeve can thus be embodied to be open at the top so that accumulating dirt can be easily removed.

Because the spring assigned to each die segment has to fulfill only the spring function, the necessary spring force can be preset through a suitable selection of material and material thickness. If only two die segments lying opposite one another are used, the outer contour can be kept narrow. In embodiments, the die segments are made of hardened tool steel and the thickness in the direction of the biased spring is about 5 mm; although other materials and thicknesses are contemplated by the invention.

The springs are preferably leaf springs, whereby the construction space in the longitudinal direction of the die can be kept small. The springs are preferably attached via bolts that can be driven into the base body. The casing sleeve can also be attached to the base body by these bolts.

Guiding the die segments in the guide slots can take place via, respectively, a bolt that can be driven in or by guide lugs that project laterally from the die segments. To make it possible to drive in the guide bolts, the die segments are provided with a through bore on their lateral outer ends.

If the material for the casing sleeve is very strong, the casing sleeve can also be used as a stop for the spreading path movement for the die segments and/or as additional support for the bearing components.

A die comprises a casing sleeve that is essentially rectangular in cross section, open at a top and attached to a base body. Guide slots lie opposite one another in the casing sleeve. Die segments are supported and guided in the guide slots. Guide mechanisms project laterally from the die segments to positively engage in the guide slots.

The die segments together with an anvil form a cavity with a cavity axis H. The die segments are supported in a transverse slidable manner in the casing sleeve. Springs are attached laterally in the base body and exert a prestressing force on the die segments and apply a restoring force to return the die segments to an original position after joining is completed. The springs are two leaf springs which bear against a back of the die segments and are fixed in the base body by fasteners that are driven into the base body. The guide mechanisms are one of laterally projecting lugs extending from the die segments and a plurality of bolts. The die segments are each provided with a through bore on lateral outer ends. Bolts (e.g., fasteners) are inserted through the bores and are accommodated in a positive manner in the guide slots.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

FIG. 1 shows a perspective exploded view of a die in accordance with the invention; and

FIG. 2 shows a perspective view of the die segments in a further exemplary embodiment in accordance with the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention.

The invention relates to a die for a tool set comprising a punch and a die for mechanically joining metal sheets lying flat one on top of another by shaping, with an anvil and die segments which, together with the anvil, form a cavity into which the joining is carried out. The die segments are supported in a slidable manner at an angle transversely, preferably orthogonally to the cavity axis against a spring force. A casing sleeve surrounds the die segments. The spreading movement preferably takes place orthogonally to the cavity axis H, but it can also be made transversely upwards or downwards.

Referring to FIG. 1, the die essentially comprises a base body 1 with an anvil 7 formed thereon, a casing sleeve 3 and two die segments 2, 2 a. The die segments 2, 2 a together with the anvil 7 form a cavity, with a cavity axis H. The die segments 2, 2 a are supported in a transverse slidable manner in the casing sleeve 3. The sliding path can be orthogonal to the cavity axis H or at an angle directed upwards or downwards.

Two leaf springs 4, 4 a are attached laterally in the base body 1. The leaf springs 4, 4 a exert a prestressing force on the die segments 2, 2 a and apply the restoring force to return the die segments 2, 2 a to their original position after joining is completed. The die segments 2, 2 a are provided with one through bore 10, 10 a each on their lateral outer ends. Fasteners such as bolts 5, 5 a can be inserted through bores 10, 10 a which are then accommodated in a positive manner in the guide slots 8, 8′; 8 a, 8 a′ provided in the casing sleeve 3, through which the die segments performing the spreading movement are guided. The bolts 5, 5 a together with the guide slots 8, 8′; 8 a, 8 a′ secure the die segments 2, 2 a from falling out.

The casing sleeve 3 is closed only at the sides. It is open at the top and at the bottom.

The leaf springs 4, 4 a, which bear against the back of the die segments 2, 2 a, are fixed in the base body 1 by fasteners such as bolts 6, 6 a that can be driven into the base body 1. At the same time, the casing sleeve 3 is also attached to the base body 1 by the fasteners such as the bolts 6, 6 a. If correspondingly high-quality materials are chosen for the casing sleeve 3, the inner wall of the casing sleeve 3 can serve as a stop limiting the spreading path for the die segments 2, 2 a and/or as an additional support for bearing components. In embodiments, the materials can be every spring steel that is highly carboniferous and hardenable or hardened by rolling. The strength of the casing sleeve, in embodiments, has a tensile strength of about 500 N/mm²; although it should be understood that other tensile strengths are also contemplated by the invention.

As FIG. 2 shows, laterally projecting lugs 9, 9 a can be embodied in the die segments 2, 2 a to guide the die segments 2, 2 a in the guide slots 8, 8′; 8 a, 8 a′ of the casing sleeve 3. The lugs 9, 9 a are embodied in one piece with the die segments 2, 2 a. Instead of lugs 9, 9 a embodied in one piece, it is also contemplated to provide four bolts that are inserted or pressed into corresponding bores provided laterally in the die segments 2, 2 a.

It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. 

1. A die for a tool set, comprising: a punch and a die structured to mechanically join metal sheets lying flat one on top of another by shaping; an anvil; die segments, together with the anvil, forming a cavity into which the joining is carried out and which are supported against a spring force in a slidable manner at an angle transversely to an axis H of the cavity; a casing sleeve surrounding the die segments, the casing sleeve being essentially rectangular in cross section, open at a top and attachable to a base body; guide slots lying parallel opposite one another in the casing sleeve which support and guide the die segments; and guides projecting laterally on the die segments for positive engagement in the guide slots.
 2. The die according to claim 1, further comprising a separate spring supported in the base body and assigned to each die segment.
 3. The die according to claim 1, wherein the die segments are two die segments arranged opposite one another.
 4. The die according to claim 2, wherein the springs are leaf springs.
 5. The die according to claim 1, wherein the springs are attached to the base body by fasteners.
 6. The die according to claim 5, wherein the casing sleeve is attached to the base body by the fasteners.
 7. The die according to claim 1, wherein the guides are bolts insertable in the die segments.
 8. The die according to claim 1, wherein the guides are lateral guide lugs embodied in one piece with the die segments.
 9. The die according to claim 1, wherein the anvil is on the base body.
 10. The die according to claim 1, wherein the casing sleeve serves as a travel-limiting stop for the die segments.
 11. The die according to claim 1, wherein the angle is orthogonal to the cavity axis H.
 12. The die according to claim 5, wherein the fasteners are bolts.
 13. The die according to claim 6, wherein the fasteners are bolts.
 14. A die comprising: a casing sleeve which is open at a top and attached to a base body; guide slots lying opposite one another in the casing sleeve; die segments supported and guided in the guide slots; and guide mechanisms projecting laterally from the die segments to positively engage in the guide slots.
 15. The die according to claim 14, wherein the die segments together with an anvil forms a cavity with a cavity axis H and the die segments are supported in a transverse slidable manner in the casing sleeve.
 16. The die according to claim 14, wherein the casing sleeve is essentially rectangular in cross section.
 17. The die according to claim 14, further comprising springs attached laterally in the base body and which exert a prestressing force on the die segments and apply a restoring force to return the die segments to an original position after joining is completed.
 18. The die according to claim 17, wherein the springs are two leaf springs which bear against a back of the die segments and are fixed in the base body by fasteners that are driven into the base body.
 19. The die according to claim 14, wherein the guide mechanisms are one of laterally projecting lugs extending from the die segments and a plurality of bolts.
 20. The die according to claim 14, wherein the die segments are each provided with a through bore on lateral outer ends, and bolts are inserted through the bores and are accommodated in a positive manner in the guide slots. 